A-Geological-Overview-Of-Digitalized

Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 DOI: 10.24411/2619-0761-2020-10013 УДК 351.02 A GEOLOGICAL OVERVIEW OF DIGITALIZED ROCK DRILL CORE SAMPLES OF ORDOVICIAN PERIOD IN ESTONIA Шоммет Ю.*, Эйнасто Р. Таллинская техническая высшая школа, г. Таллин, Эстония J. Šommet*, R. Einasto TTK University of Applied Sciences, Tallin, Estonian *E–mail: [email protected] Abstract. The aim of this paper is to give a proper overview of scanning methodology, scanned drill core samples, demonstrate sedimentary rock samples as a perfect geological material for digital scanning methodology, which helps to archive important geological information, to select necessary texture and structure designs of rock materials, and to follow its peculiarities. The scanning methodology is a perfect tool for observing and assessing all rock samples for new investigations or layer- to-layer mining planning and selecting the best mining-geological conditions and even pattern selection for decorations in architectural works. The described and used methodology is available and free for everyone: researchers, mining engineers or mining development companies as well as geologists and others. Carbonate rocks are mined worldwide but only in Estonia, one of them – limestone - is a national stone, thus mainly scanned limestone samples were used in this research. As a result, all drill core rock layers are accurately identified and the most important of them are described in detailed laboratory study. The findings are highly relevant for local and regional stratigraphy and represent the Ordovician Period in Baltic States. Keywords: Scanning methodology, oil shale, limestone, dolostone, geological information, data digitalization. Introduction. present in Estonia area. In the Ordovician igitalization helps to fix objec- period, continental seas and widespread deposi- tively and exactly the stone tion of carbonate sediments had a greater ex- texture and sedimentation tent in this period. The marine flora and fauna peculiarities; it can help to changed markedly in the course of the Ordovi- developD and document geological data and it cian period. Several major taxonomic groups can be also used at digital libraries of core (trilobites, bryozoans, echinoderms, brachio- data’s for any research. The main advantage of pods, ostracodes, chitinozoans and others) the herein used dry scanning technique its low – appeared or became common. In this respect, cost, simplicity and accessibility for everyone the Ordovician is one of the most interesting (student, geology hobbyist or researcher). A periods in the history of marine faunas, and detailed methodological description will be Estonia is among the areas in the world where given below. this fauna is well preserved and studied At the moment such sedimentary rocks as (Raukas, Teedumäe, 1997). oil shale, limestone and dolostone are mined in Oil shale resources in Estonia are notable Estonia. All of them are actively used in the (Ots, 2007). There are two oil shale types that production of different aggregates. Usually the can be found in this paper, which are wide- rock layers contain also other additional materi- spread in Estonia – dark-brown Dictyonema als, as a result, raw material quality and consti- Argillite (claystone) and light-brown oil shale tution vary from place to place in Estonia and (sedimentary Kukersite rock). Both of them the neighbouring Baltic states. belong to the Ordovician period, but light- Such geological periods as Quaternary, brown oil shale is the main type in Estonia and Devonian, Silurian, Ordovician, Cambrian, it belongs to the basal Upper Ordovician Ediacaran and Precambrian basement are formation. Oil shale beds have a stratified Содержимое этой работы может использоваться в соответствии с условиями лицензии Creative Commons Attribution 4.0. Любое дальнейшее распространение этой работы должно содержать указание на автора (ов) и название работы, цитирование в журнале и DOI. Общая и региональная геология 5 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 structure with mineral interbeds (Ots, 2007). enhancing the clarity of boundaries and con- There are fifty oil shale layers in total in North- trast. Unfortunately, it is quite inconvenient and ern Estonia. The lowest layers of the stage are unhandy, but it is considered in this paper as the most interesting from a mining viewpoint. well for methods comparison. Thin limestone interlayers separate this: pink, Such scanning results can be probably white and blue limestone or its macerals (Väli, achieved with professional digital photography Valgma, Reinsalu, 2008). equipment as well, but it involves multiple data Limestone and dolostone have been used in transfers (Mill, 2017), which inevitably causes the field of construction for thousands of years. certain distortion and inaccuracy at the quality The use of limestone as a decorative material is of the images; it is an expensive (Doehne, decreasing nowadays; modern Estonian Pinchin, 2008) and a labour-consuming process. architecture is focused on concrete, steel and The principal disadvantages of professional glass (Rähni, 2007). Polished or cut limestone, photography are the cost of all the necessary dolostone also, looks very elegant and it can be devices-instrumentations as the camera body, used as decorative stone by civil engineers and lenses and horizontal system tripod, complex architects, designers as well as interior decora- and sophisticated data storage as well as diffi- tors (Fig. 1). culties in archiving and analysing processes. As Nowadays good aggregate quality and raw a result, photographing cannot displace scan- material quality are required in all industry ning in this case and is not considered in this fields. For this purpose, representative core paper. Such equipment is justified in other re- samples of all previously described rocks of the searches when actions are needed immediately Ordovician period were used in the scanning at the field areas, which are new to the science, process as examples. Samples were studied in and waiting to be studied in fresh, untouched detail to introduce the easiest and the and natural conditions (Shu, Zi Bing, Wei- cheapest scanning technology and monitoring huen, Huang, Bo, Maciejewski, Fang, 2019). system for prospective data examples that can In this digitalization research, different be used by everyone at further investigations. types of rocks and layers of limestone and dolo- Next chapter introduce used scanning method- stone, also oil shale in some cases were used ology. (Fig. 1). The stratigraphical distribution, corre- Materials and Methods. The used scanning lation with global units and time slices of re- technique involves digital dry scanning of vised samples in the Baltic States and the Ordo- smooth rock surface and deals with the precise vician System are shown (Fig. 1.a) in Ordovi- and objective digital fixating of rock texture. cian stratigraphic chart with the successions of The limestone dry scanning method used in this main lithostratigraphical units of the Estonian study is a basic one; it was registered as Utility and Lithuanian shelves and Livonian Basin. Model No. EE00778U1 since 20.06.2008 until The numbers of the stages C1b, C1c, C2, D2, 20.06.2016 at the database of utility models in F2 were used for scanning. The formations and the Republic of Estonia to the extent specified members from the Livonian Basin and Lithua- in the Utility Models Act and was published at nian Shelf are shown in their stratigraphic suc- periodical official gazette of the Estonian Patent cession without exact correlation with the units Office (Estonian Patent Office, 2008). Gazette in the Estonian Shelf. Abbreviations used in the publication including the original texts and chart: S, Silurian; TREM., Tremadocian; Rh, translations, data in the register and notifica- Rhuddanian; Lw., Lower; Md., Middle; Up., tions published and has legal status (Estonian Upper; HUNNEB., Hunnebergian; BILLIN., Patent Office, 2008). Billingen; LASN., Lasnamägi; Vasal., Vasa- There is another similar method of sample lemma Formation. (Hints, Harperb, scanning. The method of direct scanning of Paškevičiusc, 2018). smooth rock surfaces with wet processing is The main results of this work were the well known nowadays: for the inspection of the improvement of scanning methods and digital rock’s structure and its microstructural details processing of cut and polished strips of drill the rock surface is first made wet to gain the cores that can be used for detailed core effect of smoothness of a polished surface, libraries, using simple office scanners. The Общая и региональная геология 6 Вектор ГеоНаук/Vector of Geosciences 3(2) 2020 Fig. 1a. Stratigraphic chart with correlation of regionaal and global units with time slices for Ordovician period (Hints, Harperb, Paškevičiusc, 2018) most important is that with informative scanned Each file name consists of the drill core number photographical data, it is easy to demonstrate or name and depth (for example PA45_16_37) the difference between each rock type and its which are nonrecurring throughout all drill core formations, to identify structural defect orienta- depths and thus cannot be duplicated. It is very tions, adequately assess strength as rock quality important to use colour images as this helps to designation (RQD) index, etc. To carnalize, avoid mistakes in the geological characteriza- measuring the surface of products using thin tions of samples and cross-section composition. strips is important nowadays

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